In general, a vehicle-use seat for an automobile etc. and an office chair are respectively configured that a cover material such as a seat cover is assembled to a cushion member formed of synthetic resin such as urethane foam formed into a predetermined shape so as to cover a surface of the cushion member. Further, in a vehicle-use seat and the like, the cover material is assembled so as to wrap the cushion member after a part of the cover material is fastened to a surface of the cushion member. In this case, fastening means with a plurality of hook-shaped or mushroom-shaped male engagement elements and a plurality of loop-shaped female engagement elements which are capable of being engaged with and disengaged from the male engagement elements is utilized for fastening the part of the cover material to the surface of the cushion member.
Examples of the vehicle-use seat in which a cover material is fastened to a cushion member by utilizing such fastening means are described in Japanese Patent No. 3132984 (i.e., Patent Document 1), Japanese Patent Laid-open No. 2003-79976 (i.e., Patent Document 2), and so on.
For example, as illustrated in FIG. 12, a vehicle-use seat 60 described in Patent Document 1 includes a cushion member 61 having a concave groove 61a at its surface and a cover material 62 formed by sewing a plurality of cover pieces 62a. Here, the concave groove 61a of the cushion member 61 is arranged at a position corresponding to a seam portion where the cover pieces 62a are sewn.
Further, a first fastening member 63 having a plurality of loop-shaped female engagement elements 63a on its one face is sewn to the cover material 62 along the seam portion of the cover pieces 62a. Hereinafter, the fastening member to be sewn to the cover material 62 side is defined as the first fastening member. In particular, the first fastening member 63 is sewn to the cover material 62 in a state of being curved to be loop-shaped so that the female engagement elements 63a are oriented outward. Meanwhile, a second fastening member 64 having a plurality of mushroom-shaped male engagement elements 64a is fixed to a bottom portion of the concave groove 61a which is formed at the cushion member 61. Hereinafter, the fastening member to be fixed to the cushion member 61 side is defined as the second fastening member. The second fastening member 64 is integrated with the cushion member 61 by mold-in forming.
In the vehicle-use seat 60 of Patent Document 1 having the above structure, the cover material 62 is easily fastened to the cushion member 61 by engaging the female engagement elements 63a of the first fastening member 63 which is sewn to the cover material 62 with the male engagement elements 64a of the second fastening member 64 which is fixed into the concave groove 61a of the cushion member 61.
In a vehicle-use seat described in Patent Document 2 as well, a cover material is fastened to a surface of a cushion member by engaging female engagement elements of a first fastening member which is sewn to a seam portion of the cover material with male engagement elements of a second fastening member arranged in a concave groove of the cushion member. Accordingly, the means and method to fasten the cover material to the cushion member are substantially the same as those in Patent Document 1.
Further, for example, U.S. Pat. No. 6,206,467 (i.e., Patent Document 3) describes that a cover material 73 is fastened to a cushion member 74 by utilizing first and second fastening members 71, 72 as illustrated in FIG. 13.
In Patent Document 3, a concave groove 74a of the cushion member 74 is formed deeply from a surface of the cushion member 74. Then, the second fastening member 72 is fixed to a bottom face of the concave groove 74a as being integrated with the cushion member 74. Further, the second fastening member 72 includes a base plate 72a, a plurality of hook-shaped male engagement elements 72b formed on one face of the base plate 72a, and a plurality of loop-shaped portions 72c arranged on the other face of the base plate 72a. Here, fixing strength of the second fastening member 72 against the cushion member 74 is enhanced by embedding the plurality of loop-shaped portions 72c into the cushion member 74.
The first fastening member 71 in Patent Document 3 includes a plate portion 71b having a plurality of loop-shaped female engagement elements 71a on its one face and a tape portion 71c of which one end side is sewn to the other face of the plate portion 71b. Then, the other end side of the tape portion 71c is sewn to a seam portion of the cover material 73. The first fastening member 71 fastens the cover material 73 to the cushion member 74 by stably engaging the female engagement elements 71a of the plate portion 71b with the male engagement elements 72b of the second fastening member 72 which is fixed to the bottom face of the concave groove 74a owing to the tape portion 71c even though the concave groove 74a of the cushion member 74 is deeply formed. According to description of Patent Document 3, since the first fastening member 71 and the second fastening member 72 are arranged at a deep position from the surface of the cushion member 74 as described above, the engagement state between the first and second fastening members 71, 72 is to be maintained even when a person sits on the vehicle-use seat, for example.
By the way, in a vehicle-use seat in the conventional art, a cover material is assembled to a cushion member so as to cover the cushion member by engaging an end part of the cover material with a back face of the cushion member as pulling the end portion of the cover material toward the back face so as to wrap a side face of the cushion member after covering a surface of the cushion member with the cover material and fastening the cover material at a predetermined position by utilizing the first and second fastening members as described in Patent Document 1 to 3.
Here, in the case that a part of the cover material is fastened to the cushion member before assembling the cover material to the cushion member as described above, relative positional relation between the cover material and the cushion member is to be fixed as a result of the fastening. For example, owing to occurrence of shifting of the fastening position of the cover material during fastening of the cover material to the cushion member, there has been a case of deceasing of seat appearance (i.e., finish quality) as a result of occurrence of wrinkling at the cover material caused by the shifting of the fastening position at the time of subsequent assembling of the cover material to the cushion member as engaging the end portion of the cover material with the back face of the cushion member. In the case of the above wrinkling occurrence at the cover material caused by the shifting of the fastening position, it has been required to re-perform assembling operation of the cover material after once detaching the cover material from the cushion member. Accordingly, there has been a problem of causing productivity decrease.
Further, in general, the cover material is prepared by sewing a plurality of cover pieces. Here, owing to difficulty of accurate matching in dimensions and shapes among the respective cover materials, there has been a case of variation occurrence of prepared cover materials in dimensions and shapes. In this case, if assembling operation to fasten the cover material to the cushion member is simply repeated, wrinkling is more likely to occur at the cover material assembled to the cushion member.
Accordingly, at the time of assembling the cover material, an operator has been required to carefully perform assembling operation as checking a state of the cover material etc. so as to prevent wrinkling occurrence at the cover material. As a result, there has been a problem of increase of burden to an operator while causing decrease of assembling operability of the cover material.
Hence, for example, Japanese Patent Laid-open No. 2001-197970 (i.e., Patent Document 4) discloses a vehicle-use seat 80 in which a foamed resin slab 85 is arranged between a cover material 82 and a first fastening member 83 sewn to the cover material 82 as illustrated in FIG. 14 to prevent wrinkling occurrence at the cover material 82 to be assembled to a cushion member 81.
More specifically, in the vehicle-use seat 80 of Patent Document 4, the first fastening member 83 and the foamed resin slab 85 are sewn together to the cover material 82 with sewing yarns 86 in a state that the foamed resin slab 85 is arranged between the cover material 82 and the first fastening member 83. Then, the cover material 82 is fastened to the cushion member 81 by engaging the first fastening member 83 which is sewn to the cover material 82 with a second fastening member 84 which is fixed to the cushion member 81.
According to description of Patent Document 4, positional shifting can be absorbed by the foamed resin slab 85 which is arranged between the cover material 82 and the first fastening member 83 even if a fastening position of the cover material 82 is shifted against the cushion member 81, for example. Here, it is described that wrinkling occurrence at the cover material 82 which is assembled to the cushion member 81 can be suppressed and that operability of assembling the cover material 82 and productivity can be improved accordingly as the assembling operation of the cover material 82 can be easily performed.